Better language picker

Unlike just about every website on the planet, we have a need to allow quick switching between over 356 languages or dialects, sometimes on the same page.

Wikimedia's current solution is to present a menu of 356 choices to scroll through, using the name of the language in the language, ordered by ISO code.

The problem cannot be solved by any ordering, as that will always have languages that are harder to find. It is also sub-optimal to mix code pages, listing devanagari alongside roman letters, since there is no obvious order.

So we want to do away with a scrolling menu altogether. We want to use a text input that auto-completes with suggestions, much like the search box today. However, this auto-completion also knows about all the translations we have for all language names as well as their ISO codes. So to get to German, you could type de for its ISO code or Deutsch. You could also type ge which would give you "de - Deutsch (German)" among its choices, or even the Chinese name for German. We avoid the N**2 problem since if we do not have a translation for a particular language name in a particular language, that simply doesn't become part of the choices offered.